| 摘要 |
PROBLEM TO BE SOLVED: To improve low temperature gas carburization processes to achieve faster, more economical operation though it can achieve hardened stainless steel products with superior corrosion resistance, and to provide a modified low temperature gas carburization process for case hardening stainless steel and other ferrousbased materials which allows faster carburization than possible in the past and thereby reduces the overall cost of such procedures. SOLUTION: The modified low temperature case hardening processes are concretely a process for enhancing the surface hardness of a workpiece by gas carburization comprising contacting the workpiece with a carburizing gas at an elevated carburizing temperature sufficient to promote diffusion of carbon into the surface of the workpiece so as to form a hardened case with a prescribed thickness without the formation of carbide precipitates. The instantaneous rate of carburization is more reduced during the carburization in such a manner that the swift carburization is promoted in the early stage of the carburization, and simultaneously, the formation of carbide precipitates in the latter stage of the carburization is avoided. COPYRIGHT: (C)2007,JPO&INPIT
|
